Liquid crystal displays are widely used in modem display devices due to their advantages such as portability, low power consumption, and low radiation. Generally, a liquid crystal display includes a liquid crystal module, and a backlight module for providing light beams to illuminate the liquid crystal module.
FIG. 3 is an abbreviated plan view of a conventional liquid crystal module. The liquid crystal module 10 includes a liquid crystal panel 100, a driving chip 110, and a flexible printed circuit 170. The liquid crystal panel 100 includes a main central display area 101, and a peripheral non-display area (not labeled) surrounding the display area 101. The display area 101 is where images are displayed by the liquid crystal module 10. The driving chip 110 is configured to drive the liquid crystal panel 100 to work, and is disposed at the non-display area. The flexible printed circuit 170 includes a plurality of electrical lines 173 disposed therein. The electrical lines 173 are electrically coupled to the driving chip 110, and are configured for transmitting digital data from a data source (not shown) to the driving chip 110.
FIG. 4 is an abbreviated circuit diagram of the driving chip 110 and the flexible printed circuit 170. The driving chip 110 includes a timing control circuit 140 and an interface circuit 130. The timing control circuit 140 is configured to control displaying of images on the liquid crystal panel 100, and is electrically coupled to the interface circuit 130. The interface circuit 130 is configured to receive the digital data transmitted via the electrical lines 173 of the flexible printed circuit 170. The interface circuit 130 includes a mode selection portion 135 and a plurality of display data input terminals D1˜Dn. The mode selection portion 135 includes a first mode selection terminal 131, a second mode selection terminal 132, a third mode selection terminal 133, and a fourth mode selection terminal 134. The mode selection terminals 131, 132, 133, 134 are used to receive digital codes which determine a working mode of the driving chip 110. The display data input terminals D1˜Dn are used to receive display data according to the working mode. Moreover, each of the mode selection terminals 131, 132, 133, 134 and the display data input terminals D1˜Dn corresponds to a respective pin of the driving chip 110. That is, the driving chip 110 includes n+4 pins that are used for receiving digital data.
In operation, the first mode selection terminal 131, the second mode selection terminal 132, the third mode selection terminal 133, and the fourth mode selection terminal 134 respectively receive a first mode selection signal IM0, a second mode selection signal IM1, a third mode selection signal IM2, and a fourth mode selection signal IM3 simultaneously. Each of the mode selection signals IM0, IM1, IM2, IM3 is a 1-bit binary code, and thereby a 4-bit binary code is inputted to the mode selection portion 135. The 4-bit binary code determines the working mode of the driving chip 110. The driving chip 110 then receives the display data via the display data input terminals D˜Dn according to the working mode. Relationships between the 4-bit binary code and the working mode of the driving chip 110 are shown in the following table:
IM0IM1IM2IM3WORKING MODE000016-bit interface, 68-system1000 8-bit interface, 68-system010016-bit interface, 80-system1100 8-bit interface, 80-system1010Serial Peripheral Interface (SPI)0110Setting Disabled000118-bit interface, 68-system1001 9-bit interface, 68-system010118-bit interface, 80-system1101 9-bit interface, 80-system**11Setting Disabled
In the table, an asterisk means either 0 or 1. As shown in the table, each 4-bit binary code corresponds to a working mode of the driving chip 110. For example, when the mode selection signals IM0, IM1, IM2, IM3 are respectively 0, 1, 0, 0, the 4-bit binary code is 0100, and the 4-bit binary code controls the driving chip 110 to select a working mode of 16-bit interface, 80-system. That is, the 4-bit binary code controls the driving chip 110 to instruct the interface circuit 130 to employ a so-called 16-bit interface mode to receive display data, and instruct the interface circuit 130 to receive the display data according to a so-called 80-system timing protocol. The display data is then transmitted to the timing control circuit 140 by the interface circuit 130. The timing control circuit 140 generates timing signals therein according to the display data, and outputs the timing signals and the display data to the liquid crystal panel 100. The liquid crystal panel 100 then displays images representing the display data according to the timing signals.
In the liquid crystal module 10, the working mode of the driving chip 110 is determined by the 4-bit binary code that is received by the mode selection portion 135 of the interface circuit 130. Because the 4-bit binary code is inputted to the interface circuit 130 via the mode selection terminals 131, 132, 133, 134, and these mode selection terminals 131, 132, 133, 134 respectively receive the mode selection signals IM0, IM1, IM2, IM3 transmitted via the electrical lines 173 of the flexible printed circuit 170 simultaneously, at least four mode selection terminals 131, 132, 133, 134 are necessary for forming the mode selection portion 135. That is, the driving chip 110 needs at least n+4 pins to receive digital data from the data source, with four pins thereof being used to receive the mode selection signals IM0, IM1, IM2, IM3, and n pins thereof being used to receive the display data. The four pins corresponding to the mode selection terminals 131, 132, 133, 134 cause a size of the driving chip 110 to be correspondingly large. This in turn means the driving chip 110 requires a large amount of space for bonding to the non-display area of the liquid crystal panel 100. That is, the liquid crystal panel 100 needs a large space for bonding of the driving chip 110 thereon. This limits the compactness and portability of the liquid crystal module 10.
It is, therefore, desired to provide a liquid crystal module which overcomes the above-described deficiencies.